Telephone-transmitter.



No. 672,621. Patented Apr. 23, 190|.. C. C. HUGHES.

TELEPHONE TRANSMITTER.

(Application flled Apr. 14, 1900.)

(No Model.)

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NITED STATES CHARLES C. HUGHES, OF BALTIMORE, MARYLAND.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 672,621, dated April23, 1901. Appiianun fnea April 14, 1900. serai No. 12,953.V (No moda.)

T @ZZ whom it nutty concern:

Be it known that l, CHARLES C. HUGHES, a citizen of United States,residing at Baltimore, in the State of Maryland, have invented certainnew and useful Improvements in Telephone-Transmitters andI do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

This invention relates to telephone-transmitters in general, and moreparticularly to microphone-transmitters, one object of the inventionbeing to provide a construction which, while being suitable for interioruse, will be especially iitted for exterior use and in longdistancetelephony.

A further object of the invention is to provide a construction in whichpacking will be absolutely prevented and in` which the eiciency of theinstrument will not be impaired i under Whatever conditions it may beused.

A further object of the invention is to provide a construction whereinthe variation in current intensity will be produced by variation of thearea of surface contact and to secure a maximum of variation of surfacecontact with a minimum of vibration of the diaphragm.

Further objects and advantages of the invention will be evident from thefollowing specication.

p In the drawings forming a portion of this specioation, and in whichlike numerals of reference indicate similar parts in the several views,Figure 1 is a perspective view showing the complete instrument. Fig. 2is a central longitudinal section taken through the complete instrumentand showing some of the interior parts in elevation. Fig. 3 is a detailperspective view showing one of the electrodes. Fig. 4 is a perspectiveview showing the electrode that is carried by the sound-re- Y ceivingdiaphragm.

usual shape and into which the voice is delivered.

Within the box 10 and adjacent the inclosed end thereof there is formeda shoulder 14, and against this shoulder is disposed a diaphragm 15,which is held in place by a clamping-ring 16, which may be held in placein any suitable manner, as with screws 16 or by means of threads thereonwhich engage threads upon the inner Wall of the box. '[his diaphragm 15is separated from the closed end of the box by an interspace, as shown,to permit the sound-waves which enter through the opening 12 to have themost efficient action upon the diaphragm to vibrate it.

The rear end of the box 10 is closed lby what is almost a duplicate ofthe box, and consists of a ring 20, having exterior threads21, whichengage interior threads 22, carried by the box 10, and the rear end ofthe ring 20 is closed by a disk-shaped portion 24., which correspends tothe closure of the front end of the box 1U, this portion 24 having alsoa central opening 25, which has a double function, as will be presentlyexplained.

Within the ring 2O is a should er 26, and on this shoulder is disposed adiaphragm 27, which is also held in place by a clampingring 28, which isscrewed thereagainst, the diaphragm having a binding 28 of rubber toinsulate it from rings 28 and 20. The diaphragm 27 has a central openingwhich registers with a central opening in a block 29 of insulatingmaterial which is secured on the rear face of the diaphragm 27, theopening of this block of insulating material having threads forengagement by the stem 31 of one of the electrodes of thetransmitter,and which electrode comprises also a cylindrical head 32,which is preferably formed integral with the stem, if the electrode beof metal, but consisting of a metal bolt or machine-screw engaged with acentral axial perforation in the electrode when the latter is of carbonor other non-metallic material. The rear end ot' the stem 31 is slottedtransversely for engagement by a screw-driver, whereby the stern may berotated to adj ust the head of the electrode toward and away from thediaphragm 15.

In the outer face of the head 32that is, in the face which lies in thedirection of the dia- IOO phragmvlfthere, is `ig'ormed a curvilinearslot or groove 34, the cross-sections of which present converging lines,either in the form of straight lines lying at an angle to each other orin the form of a curve ofconstantly-changing radii, so that if a ball berolled into the groove down one side of the groove the lengthof its arcof contact will vary asl it moves into the groove and also as it movesout of the groove. It will of course be understood that this will occurso long asthecross-section of the groove l is not rectangular or ofconstant radius.

Upon the inner face of the diaphragm 15 is in the diaphragm, and inorder to adjust the,

electrodes so as to get the proper normal pressure between the balls andthe electrodes upon the diaphragm it is only necessary to screw inwardlyupon the Vstem 3l, as will be understood, access to the stem beingreadily had through the opening 25 in the center of the portion 24;

After the parts are assembled in .the manner shown a-nd described acasing 45, of metal,

is adjusted to receive the box 10 and ring 2O and is in the form of acap, the rear end thereof having a closure 46, at the center of which isformed an opening 47f, surrounded by a flange 48, which is in'teriorlythreaded for en- "gagement by a collar 48', having a flange 49 which thecollar is secured vto the fron-t of the :usual magneto-box or othersupport for the transmitter. By this means the transmitter `may bereadily applied to or removed from .i

the box or support by unscrewig it from this collar.

be adjusted without taining the transmitter from itsfsupport, as will bereadily seen.

place byl the screws 16', which latter also act to hold the casing45,the ring 16 being held f tight against the diaphragm 15, which carriesthe electrode 40, and'hence the metallic casing Ais in electricalconnection with the electrode. Therefore in making connection with the stransmitter one wire may be connected with "the flange 49, while theother wire is `passed through the collar 48 and engaged u nder thevatits rear edge, and through Ithe Vmedium-of Furthermore,the electrodesmay l set-nutupon the stem 31, the insulating-i block 29v preventing allleakage or short-fcir f cuiting. Furthermore, in this construction I `amenabled and I 'prefer to make'all parts of metal of high conductivitywith the eXcep-' tionof the electrodes and the ins'ula'ting'por Vtionsabove referred to.

In practice after the parts have been asgreater area of surface contact;also, the balls that rest against the cone will when moved intothegroove have lon-ger arcs of contact, but with greater radii.` Thus allof the balls as they move inwardly increase the areas of surface contactand all of the balls as theyv 'move outwardly decrease their areas Vofsura face" contact, the resultbeing a variation which is so great as torespondgelectrically to the slightest vibration of the moving4diaphragm. In practice the balls may be held;

in contact with both walls of thegroove',and when the balls are pressedthey will wedgeinto the groove and when released will move outwardlythereof, rattlingbeing thus 4prevented and -a `maximum of variationsecu-red.

What is claimed is- J 1. A telephone transmitter` comprising adiaphragm, an electrode operablyconnected with the diaphragm and 'asecond electrode in operative relation to the first electrode toconduct, current thereto, one of the .electrodes having aA curvilinearslot presenting a concave wall and a convex wall and inwhich slot theother electrode is engaged Afor movement bottom of the slot, the secondelectrode Vhav- `ing a curvilinearvsur'face andthe different 'arcs ofvcontact between theelectrodes having different radii whereby the secondelectrode may engagea convex and aconc'avewall when rvnoved-inw`ardly toits lim-it and may be forced therebetween with an increase in areaofcontact-surface.

2. l A telephone transmitter comprising a .I 4 v diaphragm, an electrodeoperably-connected It will be noted that the `'rin'g 16 is held in withthe diaphragm and asecondelectrodein operativerelation to the iirstelectrod`e, one of the electrodes having an annular slot-or groove whichreceives the second electrode, and the second electrode having 'acurvilinear surface, the arcsof contact between-the electrodes varyingin radii as the second electrode ismoved-into and out of the firstelectrode.

3. A telephone-transmitter `,comprising a diaphragm,I an electrodeoperably connected with the diaphragm and havinga' plurality ofelectrodes in operative relation thereto to conl,duct current thereto,the firstelectrode having anannular lgroove with which the secondelectrodes are engaged, s aidggroovebeingtabeing each spherical.

4. Ina telephone-transmitter, an electrode ico over a `wallthereoftoward and awayfrom the IIO fpe'red inwardly and the plurality ofelectrodes e y having an elongated groove each of whose sections inplanes perpendicular to the direction of motion includes a plurality ofarcs of different radii and whose radii gradually vary in the differentplanes perpendicular to the direction of motion, and an additionalcoperating electrode having a curvilinear surface in contact with thewalls of the groove and whose sectionsin the same planes are arcs ofvarying radii, the radii of the arcs of normal contact of the electrodesdiffering in value.

5. A telephone-transmitter comprising an electrode having a curvedgroove which is tapered inwardly, an additional electrode having acurvilinear face in contact with the walls of said groove, and adiaphragm in operative relation to the electrodes.

6. A telephone-transmitter comprising two electrodes each of which hasan annular groove which is tapered rearwardly, a plurality of freeelectrodes engaging both grooves, said free electrodes having each acurvilinear surface and the arcs of normal contact of the electrodesdiffering in value, and a sound-receiving diaphragm in operativerelation to the electrodes.

7. A telephone-transmitter comprising two electrodes each of which has acurvilinear groove which is tapered inwardly, a plurality of freeelectrodes engaged with both grooves, said free electrodes having eachacurvilinear surface, and the arcs of normal contact of the electrodesdiering in value, and a diaphragm in operative relation to theelectrodes to vary their areas of contact-surface.

8. A telephone-transmitter comprising two electrodes each of which has acurved groove which is tapered in wardly,a plurality of sphericalelectrodes engaged with both grooves and a diaphragm in operativerelation to the electrodes.

In testimony whereof l hereunto set my hand in the presence of twowitnesses.

OHAS. C. HUGHES.

Witnesses:

I-I. E. CHANDLER, R. A. SHEPARD.

